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Intake Water Screening Equipment

Home :: Intake Water Screening Equipment :: Travelling Band Screens

Travelling Band Screens

Screening of large volumes of water meant for industrial use can be done by MACMET's Travelling Band Screens which remove floating/suspended material that pose potential danger to downstream industrial equipment.

MACMET's Travelling Band Screens consist of Basket frames fitted with screen meshes and arranged in a link chain system. The intake water flows through these baskets, with the debris left trapped behind in the baskets. The debris so collected is carried to the top by the revolving band screen. At the top, jets of water wash out the debris into a refuse disposal trench. Highly efficient spray nozzles fitted in the spray header pipe wash out the screening baskets. There is also the option of fitting an internal cleaning device for cleaning the spray nozzles of the spray header pipe.

Depending on the pattern of water flow, MACMET's Travelling Band Screens are classified into three types:

Through-Flow Band Screen

In this configuration the water flows through the screens, effectively using 50% of the submerged mesh area. Mesh sizes range from 4 to 10 mm. The retained solids are discharged into a refuse trench.

Dual-Flow Band Screen

In this configuration the water flows from outside to the inside of the screens, effectively using 100% of the submerged mesh area. Mesh sizes range from 4 to 10 mm. The retained solids are discharged into a refuse trench.

Centre-Flow Band Screen

In this configuration the water flows from inside to the outside of the screens. The configuration of the baskets ensures 150% use of the submerged mesh area. Mesh sizes range from 0.1 to 10 mm. The retained solids are discharged into an internal collecting trough.

The water flow patterns enforced by the Dual Flow Band Screen and Centre Flow Screen remove the possibility of debris being carried over. Compared to Through-Flow Screen, the above two screens are 50% and 100% more efficient respectively.

The Through-flow TBS and Dual-flow TBS have flat basket design whereas the Centre-flow TBS has a semi-circular basket design which ensures a much higher capacity for removing debris/trash. The baskets in Centre-flow TBS have a retaining plate, which gives this TBS the characteristics of a bucket elevator. The Centre-flow TBS takes the help of gravity for discharging much of the debris, thus requiring less back wash for its screens.

Centre-flow TBS can handle up to 1,00,000 cu.m flow of water per hour with optimal filtering out of debris owing to its highly efficient screening capacity. A Centre-flow TBS also scores over the other two types of TBS by requiring less civil construction owing to its higher sump level.

The mesh size is determined by the quality of water required for processing. Thus, to ensure screening out of tiny particles, fine mesh is used. In case of power utilities and desalination units, the mesh sizes are generally 1 mm to 2 mm. No further filtration required to provide clear water for the plant.

Macmet has supplied the largest Water Intake System in India consisting of 6 channels of 55000 cu.m per hour and 2 channels of 8000cu.m per hour for Nuclear Power Corporation.

Presently Macmet is commissioning a 63,000 m³ - 82,000 m³ /hr system for Gujarat Coastal Ltd.

The first Centre flow Band Screen operating in India has also been supplied to Nirma Ltd. for a capacity of 25,000 cu.m per hour with 2 mm screen opening. In Europe and other developed nations, Centre flow type Travelling Band Screens are most commonly used when compared to the other two type of screens because of the efficiency and ease of operation of the center flow TBS.